Simultaneous dual-isotope 123I/99mTc acquisition using CZT-based cameras: Toward a one-stop-shop SPECT in heart failure patients

The CZT-cameras (DNM 530c and DSPECT) have only recently been introduced, and the impact of the increased energy resolution remains unknown. This paper summarizes the evidence on the assessment of: (i) the left ventricular function, (ii) the ¹²³I/^99mTc mismatch, and (iii) the heart-to-mediastinum ratio (HMR) of ¹²³I-metaiodobenzylguanidine (MIBG) uptake under dual-isotope conditions (^99mTc and ¹²³I) using cadmium-zinc-telluride (CZT) technology. The diagnostic accuracy of CZT cameras for myocardial sympathetic innervation imaging, left ventricular function and perfusion assessment using perfusion-gated SPECT have only been established in a few studies, under single-isotope conditions. Limited evidence is available regarding simultaneous dual-isotope acquisition using CZT-cameras. However, recently reported data have shown that CZT cameras allow, in dual-isotope (¹²³I and ^99mTc) acquisitions and under routine conditions: (i) a simultaneous and accurate segmental study of myocardial innervation and perfusion (match and mismatch), (ii) the ventricular function assessment (EDV, ESV and LVEF), and (iii) the determination of the late HMR of cardiac ¹²³I-MIBG uptake in patients with heart failure. However, this latter should be performed using transaxial reconstructed images and a linear correction based on phantom data acquisitions.

Conclusion

With an increased energy resolution, the CZT cameras should become the one-stop shop SPECT for simultaneous dual-isotope ¹²³I/^99mTc acquisitions in heart failure patients, permitting to perform LV function, myocardial perfusion and innervation.